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How do you know that the time with the Airsal didn't weaken the mounts to the point that within another 300 miles they would fail? It's not something that you would necessarily see with the necked eye. Also, maybe the MHR was designed for the engines with the balancer. Again, I'm not very familiar with the Malossi product line. When I've looked at them at Treats they seemed nicely made.

The thing here is that if your engine is vibrating a lot there's probably something that should be checked out, because they shouldn't vibrate as much as you are suggesting.

How do you know that the time with the Airsal didn't weaken the mounts to the point that within another 300 miles they would fail? It's not something that you would necessarily see with the necked eye. Also, maybe the MHR was designed for the engines with the balancer.

The thing here is that if your engine is vibrating a lot there's probably something that should be checked out, because they shouldn't vibrate as much as you are suggesting.

You are probably approaching this project from the wrong angle.
The very first response by Rj got the perspective correct.

That said, define 'power'. Do you ride between stop signs, and want acceleration, or do you ride freeways and need top speed ?
These two ends of the spectrum may be better balanced by changing gearing.

Remember that it is a SYSTEM, with all parts working together.

So... standing on shoulders etc... and never one to use just a sentence when ten will do

You need to think about your riding style.
This is everything.

So you want performance and fuel economy?

That sounds like a noob statement, but the two can go hand in hand - so it's fine (within reason).
By increasing the fuel burn efficiency, you will get more power per litre of fuel.
... only that, if you are taking advantage of that extra power (which you will), you will likely burn more fuel.

Again, referring to Rj's advice... where do you need the economy?
Is it around town?

Then you'll need the stock pipe, to gain a broad power band.
You can then keep the carb lean for town conditions.

A larger atomiser diameter, a small idle jet, and push the taper further into the throttle range.
If you are using a PHBN 17.5 you could go with an A7 on notch 4 or even 5 (with testing) - GA212 atomiser for 50cc will likely be fine.

If PHBG I know both Xero and spudgun had/have their tapers hitting very late... around 40% throttle.

The engine simply sucks what it needs through the atomiser... which has proved ideal for many people.
So you gain a Jekyll & Hyde bike, that can function fine in stop start conditions, and yet when you hit the taper... boom... you fly.

But with a stock pipe (de-restricted) there is no point in fitting a high compression crank.
Such a crank is only valid, when the engine lives at very high RPM.
The higher crankcase pressure increases the speed of the gas transfer to cope with the mind blowing requirements of an engine that lives in the 10k - 13k region.

If you fit a high pressure crank into an engine that lives in the 6k to 10k region.... the additional pressure will simply push fuel down the pipe.
If memory serves me right (I can't be arsed to confirm so don't quote me)... at 10k and 20mm bore, the airspeed is 24m/s so at 13k it is 32m/s
You can see why additional pressure might be useful, to get all the gas in place, in time.

So forget fuel economy

My advice would be to take the project in stages.
De-restrict everything, and fit a 17,5 carb, and a twin air filter (or similar) to help breathing.
Then (repeating Rj again)... concentrate on the air path through the read valves.

When you've got it running nice, and your money saved... or at least spent wisely
... you can move ahead from an informed position.
You'll better know what you want to achieve.

74cc would be the next typical step.
74cc seems to provide the extra grunt and acceleration that makes the bike like a full blown motorbike.
At least, that's what I have found.

I decided to just make good power out of my bike without looking too much at fuel economy, so far I put Jasil Top Racing Competition crank, skf c3 bearings (Stage6 bearing and crank seals kit), Airsal sport 80cc.
On airsal cylinder I didn't adjust the squish, I just put both paper gaskets under the cylinder, is that a mistake?
Also what carb and pipe should I use for this setup?
I mainly ride in freeways, looking to increase in both speed and acceleration.